Fix ability to use patch on Windows CI machines (#18356)

### Description
<!-- Describe your changes. -->
Add 32-bit patch binary and infra to fallback to it. The Azure devops
Windows CIs are missing patch.exe from their git install for some reason
so the default `find_package(Patch)` fails as that is where it expects
to find it.

Remove Eigen patch. Underlying issue was fixed in source 3 years ago by
c6c84ed961
and the patch command is invalid (args are for git apply not patch).

### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->
Make usage of patch consistent across all CIs
Fix https://github.com/microsoft/onnxruntime/issues/15248

cmake/CMakeLists.txt

@@ -526,7 +526,21 @@ if(NOT WIN32 AND NOT CMAKE_SYSTEM_NAME STREQUAL "Android")
   find_package(Iconv REQUIRED)
   set(ICONV_LIB Iconv::Iconv)
 endif()
+
 find_package(Patch)
+if (WIN32 AND NOT Patch_FOUND)
+    # work around CI machines missing patch from the git install by falling back to the binary in this repo.
+    # replicate what happens in https://github.com/Kitware/CMake/blob/master/Modules/FindPatch.cmake but without
+    # the hardcoded suffixes in the path to the patch binary.
+    find_program(Patch_EXECUTABLE NAMES patch PATHS ${PROJECT_SOURCE_DIR}/external/git.Win32.2.41.03.patch)
+    if(Patch_EXECUTABLE)
+      set(Patch_FOUND 1)
+      if (NOT TARGET Patch::patch)
+        add_executable(Patch::patch IMPORTED)
+        set_property(TARGET Patch::patch PROPERTY IMPORTED_LOCATION ${Patch_EXECUTABLE})
+      endif()
+    endif()
+endif()
 if(Patch_FOUND)
   message("Patch found: ${Patch_EXECUTABLE}")
 endif()

cmake/external/eigen.cmake

@@ -1,23 +1,14 @@
-
 if (onnxruntime_USE_PREINSTALLED_EIGEN)
     add_library(eigen INTERFACE)
     file(TO_CMAKE_PATH ${eigen_SOURCE_PATH} eigen_INCLUDE_DIRS)
     target_include_directories(eigen INTERFACE ${eigen_INCLUDE_DIRS})
 else ()
-    if (onnxruntime_USE_ACL)
-        FetchContent_Declare(
-            eigen
-            URL ${DEP_URL_eigen}
-            URL_HASH SHA1=${DEP_SHA1_eigen}
-            PATCH_COMMAND ${Patch_EXECUTABLE} --ignore-space-change --ignore-whitespace < ${PROJECT_SOURCE_DIR}/patches/eigen/Fix_Eigen_Build_Break.patch
-        )
-    else()
-        FetchContent_Declare(
-            eigen
-            URL ${DEP_URL_eigen}
-            URL_HASH SHA1=${DEP_SHA1_eigen}
-        )
-    endif()
+    FetchContent_Declare(
+        eigen
+        URL ${DEP_URL_eigen}
+        URL_HASH SHA1=${DEP_SHA1_eigen}
+    )
+
     FetchContent_Populate(eigen)
     set(eigen_INCLUDE_DIRS  "${eigen_SOURCE_DIR}")
 endif()

cmake/patches/eigen/Fix_Eigen_Build_Break.patch

@@ -1,27 +0,0 @@
-diff -Naur git_org/cmake/external/eigen/Eigen/src/Core/products/GeneralBlockPanelKernel.h git/cmake/external/eigen/Eigen/src/Core/products/GeneralBlockPanelKernel.h
---- git_org/cmake/external/eigen/Eigen/src/Core/products/GeneralBlockPanelKernel.h	2019-07-17 15:27:59.540667336 -0500
-+++ git/cmake/external/eigen/Eigen/src/Core/products/GeneralBlockPanelKernel.h	2019-07-17 15:30:16.000000000 -0500
-@@ -1076,8 +1076,9 @@
-     dest = *b;
-   }
- 
--  EIGEN_STRONG_INLINE void updateRhs(const RhsScalar* b, RhsPacketx4& dest) const
--  {}
-+  EIGEN_STRONG_INLINE void updateRhs(const RhsScalar*, RhsPacketx4&) const
-+  {
-+  }
- 
-   EIGEN_STRONG_INLINE void loadRhsQuad(const RhsScalar* b, RhsPacket& dest) const
-   {
-@@ -1145,8 +1146,9 @@
-     loadRhs(b,dest);
-   }
- 
--  EIGEN_STRONG_INLINE void updateRhs(const RhsScalar* b, RhsPacketx4& dest) const
--  {}
-+  EIGEN_STRONG_INLINE void updateRhs(const RhsScalar*, RhsPacketx4&) const
-+  {
-+  }
- 
-   EIGEN_STRONG_INLINE void loadRhsQuad(const RhsScalar* b, RhsPacket& dest) const
-   {